Piston-packing.



' R. ESNAULT-PELTERIE.

PISTON PACKING.

APPLICATION FILElMuLY 6.1911.

Patented Jan. 21,1919.

2 SHEETS-SHEETI .L dcwfoo/v da@ 6 w w R. EsNAuLT-PELTERIE.

FIS-ION PACKING.

- APPLICATION FILED JULY 5, |917. 1,292,392.

. \\\\\.4//A\` 7M l fli F PtBIlIed Jan. 21, 1919.

2 sHEETs-sHEET 2 JL f f ROBERT .'ESNAULT-PELTERIE, 0F PARIS, FRANCE.

IPISTON-IPACKING.

Specication of Letters Patent.

Patented Jan. 21, 1919.

Application filed July 6, 1917. Serial No'. 179,103.

To all whom #may concern:

Be it known that I, Bonner ESNAULT- PnLTnRrn, a citizen of the Republicof France, residing in Paris, France, have invented certain new anduseful Improvements in Piston-Packings, of which the following is aspecification.

The present invention relates to a plston packing device, speciallyintended for work at very high pressures.r

The principle of the packing forming the subject-matter ofthe presentinvention consists in utilizing, for the purpose of obtainingfluidtightness, rings or washers o f eX- tremely soft metal, which crushunder pressure and become fitted with great exactness to the walls ofthe cylinder.

It is necessary however to point vout that this arrangement is not byitself sufficient to be applied to very high pressures, for it may bringabout losses of power which in .certain instances would render thearrangement inapplicable.

In fact if it is desired to make a packing consisting solely of one softmetal, arranged in such a way that the pressure crushes it and appliesit against the walls of the cylinder, one finds oneself caught betweentwo opposite conditions :-l

On the one hand it is necessary in order that the fluidtightness maybecome primed, for the elastic limitI of the metal to be far below thepressure that it is desired to obtain, but in that case, when thepressure reaches itsv maximum, the metal is crushed to such an extentthatit works its way in between the cylinder and the hardmetal partsthat are compressing it.

From this there results a jamming, a heating and a loss of power, whichrender certain applications impracticable.

The chiefv object of the present invention is to obviate thisdisadvantage, and it consists essentially of arrangingon both sides ofthe soft metal, two washers of` metal slightly harder, and then, on.both sides of these two washers, two others of metala little harderstill, and so on, right up to the piston proper, which may be of bronze,cast iron or steel.

Experience proves that if the scale of hardness is suiiicientlygraduated, there no longer occurs any spreading of the metals betweenthe rubbing surfaces, and that under these conditions the operation issatisfactory.

v of the pressure.

In the event of the piston having to work in both directions, asforinstance, a piston which is, compressing a gas and which is subjectto pressure not only during the compression stroke but also during apart of the expansion stroke, it is necessary that there should be oneach side, starting from the soft metal, a range of metals graduallybecoming harder.

Referring to the drawings Figure 1 illustrates such a packing device,designed for working in both directions.

F ig. 2, a packing designed'for working in one direction only, with aplunger piston.

Fi 3, a packing intended for working in one irection with a non-plungerpiston. FFig. 4, a modification of the packing of ig. 5, a modication ofFig. 2.

Fig. 6, another modification of Fig. 1.

Fig. 7, an improved modification of Fig. 5.

In the arrangement that is illustrated in Fig. 1, the soft metal mayconsist for instance of a sheet of lead a, comprised between two sheetsof tin or antifriction metal b, b, which are themselves comprisedbetween two sheets of silver or gold c, c, which in turn are comprisedbetween a sheet and a ieee of copper or bronze d, e.

he whole of these washers are threaded upon a rod f, which retains themby means of its ca g, and which is itself comprised in the axls of thepiston it, where it is maintained by a transverse cotter i.

It goes without saying that to enable the packing to act the slotin therod f throu h which the cotter z' passes should allow Sucient play orclearance for the cap g to be able to compress the washers under the Italso goes without saying that the depth of the central cylindricalcavity in the iston 7L, which receives the rod f, shoul ybe greater thanthe length of the said rod, for the same purpose.

In view ofthe fact that the present packing device offers a frictionalresistance which is greater in proportion as its surface of'contact withthe cylinderlis itself greater, 1t is expedient, when applying it to apump for liquid acting in one direction only, to reduce the said rubbingsurface by arranging only one of the two sets of washers of decreasinghardness. This is what is shown in Fig. 2, in which the same lettersdesignate force Lacasse the same washers and consequently do 'notrequire any fresh explanation, the only difference consisting in thefact that the piston 'mis of the plunger type.

In Fig. 3 the saine arrangement isv illustrated for1 a pump for liquid,having a nonplunger piston, and this also does not call for any furtherexplanation. j

In applying the present device there may however arise a special case,viz: one in which the conditions of temperature or the chemicalconditions do not leave such a well graduated scale of hardnessesavailable as might be desired.

In this case, in order to prevent the soft metal from working betweenthe harder metal and the cylinder wall, it is desirable to utilize thearrangement illustrated. in Fig. 4, which consists in not making theobturating washers flat but of arrangingy them in such a way that the'washer of the hardest metalmeets to join against the face of thecylinder at an acute angle, the softv metal meeting at an obtuse angleequal to the supplement of the preceding angle, these two langles 'beingfurther removed from 90o according as the difference in hardness betweenthe two metals is greater.

This is what is illustrated in Fig. 4,. for a piston arranged as in Fig..1, assuming that one has been compelled to include the lead washerdirectly between two silver washers.

Fig. 5 illustrates an arrangement equivalent to the preceding, appliedto the arrangement of Fig. 2.

In the event ofI it being desired to compress a gas up to anexceptionallyhigh pressure it is advantageous not to put a single softmetal washer in the center of the packing but to arrange several softmetal washers separated from one another by slightly harder washers.

In Fig. 6 a piston similar to that of Fig. l is outlined, but comprisingat its center a series of three lea'd washers separated by two washersof tin or antifriction metalfor instance.

Fig. -7 relates to an. improved construc tional form of the packing ofFig. 45, en-

abling a packing toV be obtained which isI more compact and morehomogeneous and therefore more capable of resisting wear and lessfragile.

The various superposed washers a, b, c, d have the faces that areintended to come into contact with one another cut to a V- shape allhaving the same degree of opening, 'in such` a way that the "saidwashersv can fit exactly into one another. r1`he upper vsurface of theirst washer a, formed of the softest metal, may be plain, and ispreferably almost iush with the upper edge of the next washer b.

The inclination of the faces of the washers that are in contact with oneanother, and consequently the angle they make with the wall of thepiston h, are determined as before according to the difference in hardnebetween the metals employed.

The various washers may advantageously be united to anotherI by weldingso as to increase the compactness of the packing.l

What l claim and desire to secure by Letters Patent of the United Statesis 1. A piston packing for high pressure apparatus, said packingcomprising several layers of metal of different hardness, the

t layer of softest metal having adjacent thereto theilayers of metal inthe order'of their Olncreasing hardness, the metal of said layer ofsoftest metal being adapted to be crushed against the sliding partagainst'which the packing bears.

2. A piston packing according to claim 1 further characterized by thelayer of softest metal being on the pressure side of the packing. j

3. A piston packing according to claim 1 further characterizedby thelayer of softest metal meeting the sliding part against-- which it bearsat an obtuse angle and the metal layers inmediately adjacent saidsoftest metal layer meeting said sliding part at an acute angle formingthe supplement t of the obtuse angle referred to. A 4. A piston packingaccording to claim 1 further characterized by plural layers of softestmetal and 'its immediately adjacent layer.

. 5. A piston packing according to claim 1 further characterized by thelayers of metal being V-shaped in cross-section.

6. A piston packing according to claim 1 further characterized by thelayers of metal being superposed [in series on either side of said layerof. softest metal.

In witness whereof l have hereunto signed my name in the presence of twosubscribing witnesses. l

Witnesses:

CHAs. P. Pimsleur, HENRI CARTIER.

